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Ant Colony Optimization (ACO) is a well-known swarm intelligence method, inspired in the social behavior of ant colonies for solving optimization problems. When facing large and complex problem instances, parallel computing techniques are usually applied to improve the efficiency, allowing ACO algorithms to achieve high quality results in reasonable(More)
Let G = (V ,E) be a graph with a distinguished set of terminal vertices K ⊆ V . We define the K-diameter of G as the maximum distance between any pair of vertices of K. If the edges fail randomly and independently with known probabilities (vertices are always operational), the diameter-constrained K-terminal reliability of G, RK(G,D), is defined as the(More)
This work presents a novel parallel micro evolutionary algorithm for scheduling tasks in distributed heterogeneous computing and grid environments. The scheduling problem in heterogeneous environments is NP-hard, so a significant effort has been made in order to develop an efficient method to provide good schedules in reduced execution times. The parallel(More)
In order to evaluate the capacity of a communication network architecture to resist to the possible faults of some of its components, several (un)reliability metrics are currently used. In this paper, we consider the K-terminal (un)reliability measure. The exact evaluation of this parameter is NP{hard problem. An alternative approach is to perform(More)
Let G= (V ,E) be a digraph with a distinguished set of terminal vertices K ⊆ V and a vertex s ∈ K . We define the s,K-diameter of G as the maximum distance between s and any of the vertices of K. If the arcs fail randomly and independently with known probabilities (vertices are always operational), the diameter-constrained s,K-terminal reliability of G,(More)
This work presents sequential and parallel evolutionary algorithms (EAs) applied to the scheduling problem in heterogeneous computing environments, a NP-hard problem with capital relevance in distributed computing. These methods have been specifically designed to provide accurate and efficient solutions by using simple operators that allow them to be later(More)
Rare event simulation requires acceleration techniques in order to i) observe the rare event and ii) obtain a valid and small confidence interval for the expected value. A "good" estimator has to be robust when rarity increases. This paper aims at studying robustness measures, the standard ones in the literature being Bounded Relative Error and Bounded(More)
This paper explores the design of a P2P architecture that sends real-time video over the Internet. The aim is to provide good quality levels in a highly dynamic P2P topology, where the frequent connections/disconnections of the nodes makes it difficult to offer the Quality-of-Experience (QoE) needed by the client. We study a multi-source streaming approach(More)